1. Technical Field
The present disclosure relates to the production of three-dimensional images, and to a method for reconstruction of the three-dimensions of an object from two-dimensional images. The present disclosure relates for example, but not exclusively, to the recognition of faces or fingerprints, robotics, microscopy, surface analysis, etc.
2. Description of the Related Art
Numerous methods of reconstructing images in three dimensions exist. Stereoscopic vision is one of the most well-known methods of three-dimensional vision. This method is based on the use of several images of an object taken from different angles, and uses extensive calculations in order to establish the correspondences between the different images. Despite advances in the calculation power of graphic processors specialized in stereoscopic vision, this method does not seem to be compatible with real-time applications, in particular for the reconstruction at a video rate of three-dimensional images, and for applications using high-resolution images. However, graphic processors capable of implementing this method exist, but their cost is incompatible with general public applications. Moreover, this method offers a limited precision as far as depth calculation is concerned.
Methods also exist consisting of acquiring several images of an immobile object from a single point of view with different focuses, to determine a depth for each pixel of the images as a function of the sharpness of the object near the pixel in each image. These methods use a high number of images and are therefore not adapted to real-time applications.
It is also known to use Time-Of-Flight (TOF) camera systems. These systems use the intervention of “LIDAR” techniques (LIght Detection And Ranging), but offer the advantage of supplying all the pixels of an image of a scene at the same time. These systems are be equipped with ultra-rapid and therefore very sensitive sensors, an ultra-rapid pulsed light source of the laser or electroluminescent diode type, a lens, and, optionally, a very selective filter. In order to reduce measurement noise, these systems calculate an average over several images. These systems are thus very costly, and supply low-resolution images.
Other systems implementing interferometric techniques are reserved for scientific and medical applications due to their very high cost, their complex implementation, and the range of measurable distances (microns).